This study investigated which life style factors were correlated with the level and the variability of systolic (SBP) and diastolic (DBP) pressure in a random population sample. Ten blood pressure readings were obtained at home in 405 men and 379 women (20 to 84 years). Each person's average pressure level was computed together with the standard deviation as index of variability. Sodium, potassium, and alcohol intake, smoking habits, social class, psychoemotional stress, and the calories spent at work and in sports were assessed from a questionnaire and from determinations on serum and on a 24-h urine sample. A P10 to P90 (10th and 90th percentile) increase of alcohol intake, as reflected by serum gamma-glutamyltransferase, was associated with a 3.2 +/- 0.9 mm Hg higher DBP in men and with a 3.1 +/- 1.6 mm Hg higher SBP and a 1.5 +/- 0.8 mm Hg higher DBP in women. A P10 to P90 increase in the calories spent in sports was accompanied by a decrease in pressure, averaging 1.5 +/- 0.8 mm Hg for DBP in men and 2.4 +/- 1.2 mm Hg and 1.8 +/- 0.8 mm Hg for SBP and DBP in women. A 2.2 +/- 0.7 mm Hg higher DBP was observed in women living in a working class area. After adjustment for age, the variability of DBP was inversely correlated with self-rated physical activity in men, whereas women living in a working class area showed a decreased SBP variability. In conclusion, in an affluent Western population, alcohol intake, participation in sports, and living in a working class area were identified as the life style factors of importance for the blood pressure level. By contrast, blood pressure variability, as measured in the present study, was only to a minor extent influenced by life style.